While it is technically possible to open an Excel file in Notepad, this is not a good idea. Excel files are binary files that contain complex formatting and data structures. When you open an Excel ...

XLS files are Excel workbook files created in Excel 97 or Excel 2003. The 2007, 2010 and 2013 versions of the program use the XLSX format by default to save workbooks, but can also use the XLS format.

There are many people who have Windows as well as Mac computers and use both these OSs. When you do so, you might sometimes face difficulties like opening a file created by one OS on the other ...